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by omnicognate 243 days ago
If you genuinely want the strongest statement of it, read The Emperor's New Mind followed by Shadows of the Mind, both by Roger Penrose.

These books often get shallowly dismissed in terms that imply he made some elementary error in his reasoning, but that's not the case. The dispute is more about the assumptions on which his argument rests, which go beyond mathematical axioms and include statements about the nature of human perception of mathematical truth. That makes it a philosophical debate more than a mathematical one.

Personally, I strongly agree with the non-mathematical assumptions he makes, and am therefore persuaded by his argument. It leads to a very different way of thinking about many aspects of maths, physics and computing than the one I acquired by default from my schooling. It's a perspective that I've become increasingly convinced by over the 30+ years since I first read his books, and one that I think acquires greater urgency as computing becomes an ever larger part of our lives.

5 comments

Can you critique my understanding of his argument?

1. Any formal mathematical system (including computers) have true statements that cannot be proven within that system.

2. Humans can see the truth of some such unprovable statements.

Which is basically Gödel's Incompleteness Theorem. https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_...

Maybe a more ELI5

1. Computers follow set rules

2. Humans can create rules outside the system of rules in which they follow

Is number 2 an accurate portrayal? It seems rather suspicious. It seems more likely that we just havent been able to fully express the rules under which humans operate.

Notably, those true statements can be proven in a higher level mathematical system. So why wouldn’t we say that humans are likewise operating in a certain system ourselves and likewise we have true statements that we can’t prove. We just wouldn’t be aware of them.
>likewise we have true statements that we can’t prove

Yes, and "can't" as in it is absolutely impossible. Not that we simple haven't been able to due to information or tech constraints.

Which is an interesting implication. That there are (or may be) things that are true which cannot be proved. I guess it kinda defies an instinct I have that at least in theory, everything that is true is provable.

That's too brief to capture it, and I'm not going to try to summarise(*). The books are well worth a read regardless of whether you agree with Penrose. (The Emperor's New Mind is a lovely, wide-ranging book on many topics, but Shadows of the Mind is only worth it if you want to go into extreme detail on the AI argument and its counterarguments.)

* I will mention though that "some" should be "all" in 2, but that doesn't make it a correct statement of the argument.

Is it too brief to capture it? Here is a one sentence statement I found from one of his slides:

>Turing’s version of Gödel’s theorem tells us that, for any set of mechanical theorem-proving rules R, we can construct a mathematical statement G(R) which, if we believe in the validity of R, we must accept as true; yet G(R) cannot be proved using R alone.

I have no doubt the books are good but the original comment asked about steelmanning the claim that AGI is impossible. It would be useful to share the argument that you are referencing so that we can talk about it.

That's a summary of Godel's theorem, which nobody disputes, not of Penrose's argument that it implies computers cannot emulate human intelligence.

I'm really not trying to evade further discussion. I just don't think I can sum that argument up. It starts with basically "we can perceive the truth not only of any particular Godel statement, but of all Godel statements, in the abstract, so we can't be algorithms because an algorithm can't do that" but it doesn't stop there. The obvious immediate response is to say "what if we don't really perceive its truth but just fool ourselves into thinking we do?" or "what if we do perceive it but we pay for it by also wrongly perceiving many mathematical falsehoods to be true?". Penrose explored these in detail in the original book and then wrote an entire second book devoted solely to discussing every such objection he was aware of. That is the meat of Penrose' argument and it's mostly about how humans perceive mathematical truth, argued from the point of view of a mathematician. I don't even know where to start with summarising it.

For my part, with a vastly smaller mind than his, I think the counterarguments are valid, as are his counter-counterarguments, and the whole thing isn't properly decided and probably won't be for a very long time, if ever. The intellectually neutral position is to accept it as undecided. To "pick a side" as I have done is on some level a leap of faith. That's as true of those taking the view that the human mind is fundamentally algorithmic as it is of me. I don't dispute that their position is internally consistent and could turn out to be correct, but I do find it annoying when they try to say that my view isn't internally consistent and can never be correct. At that point they are denying the leap of faith they are making, and from my point of view their leap of faith is preventing them seeing a beautiful, consistent and human-centric interpretation of our relationship to computers.

I am aware that despite being solidly atheist, this belief (and I acknowledge it as such) of mine puts me in a similar position to those arguing in favour of the supernatural, and I don't really mind the comparison. To be clear, neither Penrose nor I am arguing that anything is beyond nature, rather that nature is beyond computers, but there are analogies and I probably have more sympathy with religious thinkers (while rejecting almost all of their concrete assertions about how the universe works) than most atheists. In short, I do think there is a purely unique and inherently uncopyable aspect to every human mind that is not of the same discrete, finite, perfectly cloneable nature as digital information. You could call it a soul, but I don't think it has anything to do with any supernatural entity, I don't think it's immortal (anything but), I don't think it is separate from the body or in any sense "non-physical", and I think the question of where it "goes to" when we die is meaningless.

I realise I've gone well beyond Penrose' argument and rambled about my own beliefs, apologies for that. As I say, I struggle to summarise this stuff.

Thank you for taking the time to clarify. Lots to chew on here.
Gonna grab those, thanks for the recommendation.

If you are interested in the opposite point of view, I can really recommend "Vehicles: Experiments in Synthetic Psychology" by V. Braitenberg.

Basically builds up to "consciousness as emergent property" in small steps.

Thanks, I will have a read of that. The strongest I've seen before on the opposing view to Penrose was Daniel Dennett.
Dennett, Darwins Dangerous Idea, p448

... No wonder Penrose has his doubts about the algorithmic nature of natural selection. If it were, truly, just an algorithmic process at all levels, all its products should be algorithmic as well. So far as I can see, this isn't an inescapable formal contradiction; Penrose could just shrug and propose that the universe contains these basic nuggets of nonalgorithmic power, not themselves created by natural selection in any of its guises, but incorporatable by algorithmic devices as found objects whenever they are encountered (like the oracles on the toadstools). Those would be truly nonreducible skyhooks.

Skyhook is Dennett's term for an appeal to the supernatural.

Braitenberg emphasised the importance of analog circuits though.
To be honest, the core of Penrose’s idea is pretty stupid. That we can understand mathematics despite incompleteness theorem being a thing, therefore our brains use quantum effects allowing us to understand it. Instead of just saying, you know, we use a heuristic instead and just guess that it’s true. I’m pretty sure a classical system can do that.
I'm sure if you email him explaining how stupid he is he'll send you his Nobel prize.

Less flippantly, Penrose has always been extremely clear about which things he's sure of, such as that human intelligence involves processes that algorithms cannot emulate, and which things he puts forward as speculative ideas that might help answer the questions he has raised. His ideas about quantum mechanical processes in the brain are very much on the speculative side, and after a career like his I think he has more than earned the right to explore those speculations.

It sounds like you probably would disagree with his assumptions about human perception of mathematical truth, and it's perfectly valid to do so. Nothing about your comment suggests you've made any attempt to understand them, though.

I want to ignore the flame fest developing here. But, in case you are interested in hearing a doubter's perspective, I'll try to express one view. I am not an expert on Penrose's ideas, but see this as a common feature in how others try to sell his work.

Starting with "things he's sure of, such as that human intelligence involves processes that algorithms cannot emulate" as a premise makes the whole thing an exercise in Begging the Question when you try to apply it to explain why an AI won't work.

"That human intelligence involves processes that algorithms cannot emulate" is the conclusion of his argument. The premise could be summed up as something like "humans have complete, correct perception of mathematical truth", although there is a lot of discussion of in what sense it is "complete" and "correct" as, of course, he isn't arguing that any mathematician is omniscient or incapable of making a mistake.

Linking those two is really the contribution of the argument. You can reject both or accept both (as I've said elsewhere I don't think it's conclusively decided, though I know which way my preferences lie), but you can't accept the premise and reject the conclusion.

Hmm, I am less than certain this isn't still begging the question, just with different phrasing. I.e. I see how they are "linked" to the point they seem almost tautologically the same rather than a deductive sequence.
You realise that this isn’t even a reply so much as a series of insults dressed up in formal language?

Yes, of course you do.

It wasn't intended as an insult and I apologise if it comes across as such. It's easy to say things on the internet that we wouldn't say in person.

It did come from a place of annoyance, after your middlebrow dismissal of Penrose' argument as "stupid".

And you do it again, you apologise while insulting me. When challenged you refuse to defend the points you brought up, so that you can pretend to be right rather than be proved wrong. Incompleteness theorem is where the idea came from, but you don’t want to discuss that, you just want to drop the name, condescend to people and run away.
Here are the substantive things you've said so far (i.e. the bits that aren't calling things "stupid" and taking umbridge at imagined slights):

1. You think that instead of actually perceiving mathematical truth we use heuristics and "just guess that it's true". This, as I've already said, is a valid viewpoint. You disagree with one of Penrose' assumptions. I don't think you're right but there is certainly no hard proof available that you're not. It's something that (for now, at least) it's possible to agree to disagree on, which is why, as I said, this is a philosophical debate more than a mathematical one.

2. You strongly imply that Penrose simply didn't think of this objection. This is categorically false. He discusses it at great length in both books. (I mentioned such shallow dismissals, assuming some obvious oversight on his part, in my original comment.)

3 (In your latest reply). You think that Godel's incompleteness theorem is "where the idea came from". This is obviously true. Penrose' argument is absolutely based on Godel's theorem.

4. You think that somehow I don't agree with point 3. I have no idea where you got that idea from.

That, as far as I can see, is it. There isn't any substantive point made that I haven't already responded to in my previous replies, and I think it's now rather too late to add any and expect any sort of response.

As for communication style, you seem to think that writing in a formal tone, which I find necessary when I want to convey information clearly, is condescending and insulting, whereas dismissing things you disagree with as "stupid" on the flimsiest possible basis (and inferring dishonest motives on the part of the person you're discussing all this with) is, presumably, fine. This is another point on which we will have to agree to disagree.

The dismissal is on point.

The whole category of ideas of "Magic Fairy Dust is required for intelligence, and thus, a computer can never be intelligent" is extremely unsound. It should, by now, just get thrown out into the garbage bin, where it rightfully belongs.

In what way is it unsound?

To be clear, any claim that we have mathematical proof that something beyond algorithms is required is unsound, because the argument is not mathematical. It rests on assumptions about human perception of mathematical truth that may or may not be correct. So if that's the point you're making I don't dispute it, although to say an internally consistent alternative viewpoint should be "thrown out into the garbage" on that basis is unwarranted. The objection is just that it doesn't have the status of a mathematical theorem, not that it is necessarily wrong.

If, on the other hand you think that it is impossible for anything more than algorithms to be required, that the idea that the human mind must be equivalent to an algorithm is itself mathematically proven, then you are simply wrong. Any claim that the human mind has to be an algorithm rests on exactly the same kind of validly challengable, philosophical assumptions (specifically the physical Church-Turing thesis) that Penrose' argument does.

Given two competing, internally consistent world-views that have not yet been conclusively separated by evidence, the debate about which is more likely to be true is not one where either "side" can claim absolute victory in the way that so many people seem to want to on this issue, and talk of tossing things in the garbage isn't going to persuade anybody that's leaning in a different direction.

It is unsound because: not only it demands an existence of a physical process that cannot be computed (so far, none found, and not for the lack of searching), but it also demands that such a physical process would conveniently be found to be involved in the functioning of a human brain, and also that it would be vital enough that you can't just replace it with something amenable to computation at a negligible loss of function.

It needs too many unlikely convenient coincidences. The telltale sign of wishful thinking.

At the same time: we have a mounting pile of functions that were once considered "exclusive to human mind" and are now implemented in modern AIs. So the case for "human brain must be doing something Truly Magical" is growing weaker and weaker with each passing day.

This is the usual blurring of lines you see in dismissals of Penrose. You call the argument "unsound" as if it contains some hard error of logic and can be dismissed as a result, but what you state are objections to the assumptions (not the reasoning) based on your qualitative evaluation of various pieces of evidence, none of which are conclusive.

There's nothing wrong with seeing the evidence and reaching your own conclusions, but I see exactly the same evidence and reach very different ones, as we interpret and weight it very differently. On the "existence of a physical process that cannot be computed", I know enough of physics (I have a degree in it, and a couple of decades of continued learning since) to know how little we know. I don't find any argument that boils down to "it isn't among the things we've figured out therefore it doesn't exist" remotely persuasive. On the achievements of AI, I see no evidence of human-like mathematical reasoning in LLMs and don't expect to, IMO demos and excitable tweets notwithstanding. My goalpost there, and it has never moved and never will, is independent, valuable contributions to frontier research maths - and lots of them! I want the crank-the-handle-and-important-new-theorems-come-out machine that people have been trying to build since computers were invented. I expect a machine implementation of human-like mathematical thought to result in that, and I see no sign of it on the horizon. If it appears, I'll change my tune.

I acknowledge that others have different views on these issues and that however strongly I feel I have the right of it, I could still turn out to be wrong. I would enjoy some proper discussion of the relative merits of these positions, but it's not a promising start to talk about throwing things in the garbage right at the outset or, like the person earlier in this thread, call the opposing viewpoint "stupid".

There is no "hard error of logic" in saying "humans were created by God" either. There's just no evidence pointing towards it, and an ever-mounting pile of evidence pointing otherwise.

Now, what does compel someone to go against a pile of evidence this large and prop up an unsupported hypothesis that goes against it not just as "a remote and unlikely possibility, to be revisited if any evidence supporting it emerges", but as THE truth?

Sheer wishful thinking. Humans are stupid dumb fucks.

Most humans have never "contributed to frontier research maths" in their entire lives either. I sure didn't, I'm a dumb fuck myself. If you set the bar of "human level intelligence" at that, then most of humankind is unthinking cattle.

"Advanced mathematical reasoning" is a highly specific skill that most humans wouldn't learn in their entire lives. Is it really a surprise that LLMs have a hard time learning it too? They are further along it than I am already.

I don't know if we're even able to continue with the thread this old, but this is fun so I'll try to respond.

You're correct to point out that defending my viewpoint as merely internally consistent puts me in a position analogous to theists, and I volunteered as much elsewhere in this thread. However, the situation isn't really the same since theists tend to make wildly internally inconsistent claims, and claims that have been directly falsified. When theists reduce their ideas to a core that is internally consistent and has not been falsified they tend to end up either with something that requires surrendering any attempt at establishing the truth of anything ourselves and letting someone else merely tell us what is and is not true (I have very little time for such views), or with something that doesn't look like religion as typically practised at all (and which I have a certain amount of sympathy for).

As far as our debate is concerned, I think we've agreed that it is about being persuaded by evidence rather than considering one view to to have been proven or disproven in a mathematical sense. You could consider it mere semantics, but you used the word "unsound" and that word has a particular meaning to me. It was worth establishing that you weren't using it that way.

When it comes to the evidence, as I said I interpret and weight it differently than you. Merely asserting that the evidence is overwhelmingly against me is not an effective form of debate, especially when it includes calling the other position "stupid" (as has happened twice now in this thread) and especially not when the phrase "dumb fuck" is employed. I know I come across as comically formal when writing about this stuff, but I'm trying to be precise and to honestly acknowledge which parts of my world view I feel I have the right to assert firmly and which parts are mere beliefs-on-the-basis-of-evidence-I-personally-find-persuasive. When I do that, it just tends to end up sounding formal. I don't often see the same degree of honesty among those I debate this with here, but that is likely to be a near-universal feature HN rather than a failing of just the strong AI proponents here. At any rate "stupid dumb fucks" comes across as argument-by-ridicule to me. I don't think I've done anything to deserve it and it's certainly not likely to change my mind about anything.

You've raised one concrete point about the evidence, which I'll respond to: you've said that the ability to contribute to frontier research maths is posessed only by a tiny number of humans and that a "bar" of "human level" intelligence set there would exclude everyone else.

I don't consider research mathematicians to possess qualitatively different abilities to the rest of the population. They think in human ways, with human minds. I think the abilities that are special to human mathematicians relative to machine mathematicians are (qualitatively) the same abilities that are special to human lawyers, social workers or doctors relative to machine ones. What's special about the case of frontier maths, I claim, is that we can pin it down. We have an unambiguous way of determining whether the goal I decided to look for (decades ago) has actually been achieved. An important-new-theorem-machine would revolutionise maths overnight, and if and when one is produced (and it's a computer) I will have no choice but to change my entire world view.

For other human tasks, it's not so easy. Either the task can't be boiled down to text generation at all or we have no unambiguous way to set a criterion for what "human-like insight" putatively adds. Maths research is at a sweet spot: it can be viewed as pure text generation and the sort of insight I'm looking for is objectively verifiable there. The need for it to be research maths is not because I only consider research mathematicians to be intelligent, but because a ground-breaking new theorem (preferably a stream of them, each building on the last) is the only example I can think of where human-like insight would be absolutely required, and where the test can be done right now (and it is, and LLMs have failed it so far).

I dispute your "level" framing, BTW. I often see people with your viewpoint assuming that the road to recreating human intelligence will be incremental, and that there's some threshold at which success can be claimed. When debating with someone who sees the world as I do, assuming that model is begging the question. I see something qualitative that separates the mechanism of human minds from all computers, not a level of "something" beyond which I think things are worthy of being called intelligent. My research maths "goal" isn't an attempt to delineate a feat that would impress me in some way, while all lesser feats leave me cold. (I am already hugely impressed by LLMs.) My "goal" is rather an attempt to identify a practically-achievable piece of evidence that would be sufficient for me to change my world view. And that, if it ever happens, will be a massive personal upheaval, so strong evidence is needed - certainly stronger than "HN commenter thinks I'm a dumb fuck".

AI does not need to be conscious for it to harm us.
Isnt the question more if it needs to be conscious to actually be intelligent?